1. Field of the Invention
The present invention relates to a method for forming a coating film with a relief pattern of decorative or artistic nature.
2. Discussion of Background
In recent years, reflecting demands for high quality products and diversification of demands by consumers, artistic or decorative products have been in demand which have coating films with relief patterns applied to various products including household electric appliances and building materials.
Heretofore, the following methods have been known as typical methods for applying relief patterns to such products:
(a) A method of coating a coating material having an additive having poor compatibility with the binder resin, such as silicone oil or an alkyl vinyl ether-type defoaming agent, incorporated therein (Japanese Unexamined Patent Publication No. 160670/1984).
(b) A method of coating a coating material having a foaming agent incorporated therein (Japanese Examined Patent Publications No. 6278/1988 and No. 11315/1990).
(c) A method of embossing an uncured coating film by means of an embossing plate (Japanese Examined Patent Publications No. 40076/1987 and No. 59030/1989).
However, the method (a) employs cissing and the method (b) employs foaming, to form coating films with speck-like relief patterns. Although artistic or decorative coating films may be thereby formed, it is thereby impossible to form optional desired relief patterns. Further, such methods have a problem that unless the amount of the additive is adjusted properly, the relief patterns tend to be non-uniform whereby the decorative or artistic nature tends to be impaired, and coating defects tend to result.
On the other hand, the above method (c) is capable of forming any desired relief pattern. However, this method cannot be applied to a thin film of a few tens micrometer. Further, this method is not suitable for the production of small quantities of various products. Furthermore, this method has a problem that the production efficiency is poor because of an increase in the number of process steps.